mpir/mpn/x86_64/sub_n.as

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; AMD64 mpn_sub_n -- Subtract two limb vectors of the same length > 0 and
; store difference in a third limb vector.
;
; Copyright 2004 Free Software Foundation, Inc.
;
; Copyright 2008 William Hart
;
; This file is part of the MPIR Library.
;
; The MPIR Library is free software; you can redistribute it and/or
; modify it under the terms of the GNU Lesser General Public License as
; published by the Free Software Foundation; either version 2.1 of the
; License, or (at your option) any later version.
;
; The MPIR Library is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
; Lesser General Public License for more details.
;
; You should have received a copy of the GNU Lesser General Public
; License along with the MPIR Library; see the file COPYING.LIB. If
; not, write to the Free Software Foundation, Inc., 51 Franklin Street,
; Fifth Floor, Boston, MA 02110-1301, USA.
;
; cycles/limb
; Hammer: 3.0
;
;
; INPUT PARAMETERS
; rp rdi
; up rsi
; vp rdx
; n rcx
%include 'yasm_mac.inc'
BITS 64
GLOBAL_FUNC mpn_sub_n
lea rsi, [rsi+rcx*8]
lea rdi, [rdi+rcx*8]
lea rdx, [rdx+rcx*8]
neg rcx
xor eax, eax ; clear cy
align 4 ; minimal alignment for claimed speed
loop1: ; do the subtraction in a loop
mov rax, [rsi+rcx*8]
mov r10, [rdx+rcx*8]
sbb rax, r10
mov [rdi+rcx*8], rax
inc rcx
jne loop1
mov rax, rcx ; zero rax
adc rax, rax ; return borrow
ret